Do you know the most peculiar thing about the shortlist for this year’s Stirling Prize, the winner of which, Zaha Hadid’s Maxxi Museum in Rome, was announced on Saturday night? Go on, take a look. See anything odd? First off, there was no building by Norman Foster or Richard Rogers on it. A significant miracle. Second, and not unrelated, half of it was made up of architects who have never been on the shortlist before and could reasonably be called “young” — which, in the queerly geriatric world of architecture, means under the age of 50. This, I think, is a watershed moment.

Part of it is demographics, the maturing of a new cohort of architects distant enough in age from those twin titans of…